🤖 fix pandoc action

.github/workflows/deploy_docs.yml

@@ -10,11 +10,14 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3
+
       - name: Set up Python
         uses: actions/setup-python@v4
         with:
           python-version: "3.x"
 
+      - uses: docker://pandoc/core:2.9
+
       - name: Install dependencies
         run: |
           pip install sphinx nbsphinx sphinx-rtd-theme pandoc